Machine

ABSTRACT

A machine including: a general-purpose power source that is a power source for general purposes and is configured to operate within a first operating range for a predetermined physical quantity; a driven body to be driven by power of the general-purpose power source; and a control device for outputting an instruction to the general-purpose power source, wherein a second operating range is defined for the predetermined physical quantity, and the control device instructs the general-purpose power source to operate within the second operating range when the driven body is driven.

INCORPORATION BY REFERENCE

The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2021-212845 filed on Dec. 27, 2021. The content of the application is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a machine.

Description of the Related Art

Conventionally, regarding a machine on which a general-purpose power source is mounted, in order to avoid an excessive increase in temperature of the general-purpose power source, there is technology implemented to control the general-purpose power source by providing a sensor for detecting the temperature. For example, there is known technology for an electrically driven vehicle that prevents loss of dynamic braking by detecting the temperature of a brake resistor, which consumes electric power generated during regenerative control of an electric motor as heat, by a sensor, and controlling the electric motor to reduce an increase in the temperature (see International Publication No. WO2019/163052).

However, regarding a general-purpose power source to be mounted on a machine, a load placed on the general-purpose power source can vary significantly depending on the type of machine. For example, in cases in which a machine on which an engine is mounted as a general-purpose power source is a power shovel or a lawn mower, a load placed on the engine is completely different even if the same engine is used. Placing an unexpected load on a general-purpose power source, or a work machine on which a general-purpose power source is mounted, can be a cause of breakage. It is a big problem to appropriately control the general-purpose power source when the load varies.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to protect a machine, and a general-purpose power source mounted on a machine.

SUMMARY OF THE INVENTION

One aspect of the present invention to solve the problem is a machine including: a general-purpose power source that is a power source for general purposes and is configured to operate within a first operating range for a predetermined physical quantity; a driven body to be driven by power of the general-purpose power source; and a control device for outputting an instruction to the general-purpose power source, wherein a second operating range is defined for the predetermined physical quantity, and the control device instructs the general-purpose power source to operate within the second operating range when the driven body is driven.

One aspect of the present invention has achieved the object of protecting a machine, and a general-purpose power source mounted on a machine.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view of a work machine;

FIG. 2 is a functional block diagram of a control device;

FIG. 3 is a flowchart of a general-purpose power source control operation performed by the control device;

FIG. 4 is a flowchart of a general-purpose power source stop operation performed by the control device;

FIG. 5 is an explanatory view for an operating range; and

FIG. 6 is an explanatory view for control performed by the control device having a plurality of operating ranges.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an embodiment of the present invention will be explained with reference to the drawings. A work machine will be described below as an example of a “machine” according to the present invention.

EMBODIMENT

FIG. 1 is a view of the work machine according to the present embodiment.

A power shovel 5 is a work machine that includes: a general-purpose power source 16 that is a power source for general purposes; a work unit 15 as a driven body driven by power of the general-purpose power source 16; and a control device 10 (second processor) for outputting an instruction to the general-purpose power source 16, and performs various kinds of work by driving the work unit 15. The work unit 15 includes bucket and arm.

The general-purpose power source 16 is a general-purpose unit that has: a motor 19; a battery 20 for supplying electric power to the motor 19; and a power source control drive 12 (first processor) for controlling the motor 19, and is configured to be capable of being incorporated as the power source not only into the power shovel 5, but also into various types of devices. Moreover, this general-purpose power source 16 is configured to operate within a first operating range A for a predetermined physical quantity. The predetermined physical quantity is a physical quantity related to the rating of each unit, such as a motor 19 and a battery 20, and, for example, a current, a voltage, a temperature, an operation time, the number of revolutions, and the remaining battery capacity. In addition to these examples, the physical quantity may be humidity, weather, time, illuminance, atmospheric pressure, altitude, a predetermined gas density, acceleration, vibration, etc. Further, in a case in which the general-purpose power source 16 has an internal combustion engine operated by fuel instead of the motor 19, the predetermined physical quantity may be the remaining fuel amount instead of the remaining battery capacity.

Furthermore, the power shovel 5 has a sensor 27 that detects the predetermined physical quantity in the work unit 15, and outputs the detected value to the control device 10 and the power source control device 12 of the general-purpose power source 16. In the present embodiment, the detected value detected by the sensor 27 is an operating temperature.

Additionally, for the power shovel 5, a second operating range B for the predetermined physical quantity is defined on the basis of marginal performance of components of the work unit 15. The second operating range B is stored in the control device 10 in advance.

The control device 10 is configured to instruct the general-purpose power source 16 to operate within the second operating range B when the work unit 15 is driven.

In other words, the first operating range A is defined to protect the marginal performance of the general-purpose power source 16 as long as the detected value detected by the sensor 27 mounted on the power shovel 5 is within the first operating range A. Moreover, the second operating range B is defined to protect the marginal performance of the work unit 15 as long as the detected value detected by the sensor 27 mounted on the power shovel 5 is within the second operating range B.

It should be noted that not only one, but also a plurality of general-purpose power sources 16 may be mounted on the power shovel 5. Considerable examples of the power shovel 5 include a snow blower having a snow blowing unit on the work unit 15, a cultivator having a cultivating device on the work unit 15, and a lawn mower having a mowing blade on the work unit 15, as well as a power shovel.

FIG. 2 is a view showing a functional configuration of the control device 10.

The control device 10 has a computer including: a processor such as a central processing unit (CPU) and a micro-processing unit (MPU); a memory device such as read only memory (ROM) and random access memory (RAM); a storage device such as a hard disk drive (HDD) and a solid state drive (SSD); and an interface circuit for connecting the general-purpose power source 16 (particularly, the power source control device 12), the sensor 27, and so on. Then, the control device 10 realizes various functional configurations shown in FIG. 2 by causing the processor to execute a program stored in the memory device or the storage device.

In short, the control device 10 includes a storage unit 40 (memory), a sensor detected value acquisition unit 17, and a determination unit 18 as the functional configurations.

The storage unit 40 stores a control program of the control device 10, and the second operating range B.

The sensor detected value acquisition unit 17 acquires a detected value detected by the sensor 27.

The determination unit 18 compares the detected value acquired by the sensor detected value acquisition unit 17 with the second operating range B, and determines what kind of control is to be performed.

The power source control device 12 has a computer including: a processor such as a central processing unit (CPU) and a micro-processing unit (MPU); a memory device such as read only memory (ROM) and random access memory (RAM); a storage device such as a hard disk drive (HDD) and a solid state drive (SSD); and an interface circuit for connecting the control device 10, the sensor 27, and so on. Then, by causing the processor to execute a program stored in the memory device or the storage device, the motor 19 is controlled to generate power, and a control function for driving the work unit 15 by the power is realized.

Here, the power source control device 12 has the first operating range A (FIG. 1 ) stored in the memory device or the storage device in advance. According to general-purpose specifications, the power source control device 12 controls the motor 19, on the basis of the value detected by the sensor 27, so that the predetermined physical quantity falls within the first operating range A. Moreover, when an instruction for the second operating range B (FIG. 1 ) is given by the control device 10, the power source control device 12 controls the motor 19, on the basis of the value detected by the sensor 27, so that the predetermined physical quantity falls within the second operating range B.

FIG. 3 is a flowchart of a comparison and determination operation for a value detected by the sensor 27 and the second operating range B. Specifically, the control device 10 is an aspect having a determination unit 18 for determining whether or not the value detected by the sensor 27 is outside the second operating range B. A CPU 32 realizes the function of the determination unit 18 by executing the program stored in the storage unit 40. The control device 10 acquires, at the sensor detected value acquisition unit 17, a detected value detected by the sensor 27 (step SA1). The determination unit 18 compares the detected value with the second operating range B, and determines whether or not the detected value is outside the second operating range B (step SA2). The detected value outside the second operating range B means specifically that the detected value is greater than a higher limit value H1 of the second operating range B, or the detected value is smaller than a lower limit value L1 of the second operating range B. It should be noted that a higher limit value H0 of the first operating range A is greater than the higher limit value of the second operating range B. A lower limit value L0 of the first operating range A is smaller than the lower limit value of the second operating range B (see FIG. 5 ). If the detected value is outside the second operating range B (step SA2: YES), the control device 10 gives a warning to an operator of, for example, the power shovel 5 through an input/output unit 50 (step SA3). If the detected value is within the second operating range B (step SA2: NO), the control device 10 returns to step SA1. It should be noted that at least one of the higher limit value H1 and the lower limit value L1 of the second operating range B may be changeable.

FIG. 4 is a flowchart showing a stop operation that is performed by the control device 10. The control device 10 acquires, at the sensor detected value acquisition unit 17, a detected value detected by the sensor 27 (step SB1). The determination unit 18 compares the detected value with the second operating range B stored in the storage unit 40, and determines whether or not the detected value is outside the second operating range B (step SB2). If the detected value is outside the second operating range B (step SB2: YES), the control device 10 instructs the power source control device 12 to perform a protection operation for protecting the general-purpose power source 16 (step SB3). Here, the protection operation is an operation for making a heavily protected operating state for the general-purpose power source 16 by operating with a reduced number of revolutions of the motor 19, or the like. The operator of the power shovel 5 may input, from the input/output unit 50, how the protection operation is to be performed. Moreover, when the control device 10 instructs the general-purpose power source 16 to perform the protection operation, the control device 10 may output to the input/output unit 50 a warning display, and generate a warning sound for the operator. The input/output unit 50 includes, for example, a display and a keyboard.

The determination unit 18 determines whether or not the detected value is greater than a first stopping threshold value H2 stored in the storage unit 40, or smaller than a second stopping threshold value L2 (see FIG. 5 ). If the detected value is greater than the first stopping threshold value H2 or smaller than the second stopping threshold value L2, the control device 10 stops the operation of the general-purpose power source 16 (step SB5).

If the determination unit 18 compares the detected value with the second operating range B, and determines that the detected value is within the second operating range B (step SB2: NO), the control device 10 returns to step SB1. If the detected value is equal to or smaller than the first stopping threshold value H2, and equal to or greater than the second stopping threshold value L2 (step SB4: NO), the control device 10 returns to step SB3.

It should be noted that the first stopping threshold value H2 is preferably greater than the higher limit value H1 of the second operating range B, and smaller than the higher limit value H0 of the first operating range A. Moreover, the second stopping threshold value L2 is preferably smaller than the lower limit value L1 of the second operating range B, and greater than the lower limit value L0 of the first operating range A.

FIG. 5 is an explanatory view about the operating ranges in the present embodiment. The horizontal axis indicates the operating temperature of the power source. Specially, it is indicated that the first operating range A is defined as a range between the lower limit value L0 and the higher limit value H0. Further, it is indicated that the second operating range B stored by the control device 10 is defined as a range between the lower limit value L1 and the higher limit value H1. Furthermore, FIG. 5 shows the relationship among the first stopping threshold value H2, the second stopping threshold value L2, the first operating range A, and the second operating range B explained in FIG. 4 .

As one modified embodiment, it is considered that, when the detected value detected by the sensor 27 exceeds a threshold value provided outside the second operating range B, the control device 10 instructs the power source control device 12 to stop the general-purpose power source 16. Specifically, when the detected value reaches the first stopping threshold value or the second stopping threshold value, the control device 10 performs stopping-control on the power source control device 12.

As another modified embodiment, it is considered an aspect in which the determination unit 18 of the control device 10 is provided with a plurality of operating ranges, in advance, for comparison with the detected value, and determination. In other words, this is a case in which a first protection range for the work machine is selectable from a plurality of predetermined operating ranges.

This modified embodiment shows a case in which the work machine is a lawn mower. In FIG. 6 , the horizontal axis indicates the number of revolutions of an engine, which is detected by the sensor 27, the number of revolutions increasing from left to right. A third operating range C corresponding to the rating of the general-purpose power source 16 alone is defined by a higher limit value R0. In the case of the lawn mower, the load placed on the general-purpose power source 16 varies depending on a work target. For example, in a case in which work is carried out in a field of many plants having hard stems, since the load on a mowing blade is high, it is likely that increasing the number of revolutions will lead to breakage of the mowing blade as the work unit 15. However, in a case in which work is carried out to mow soft grass in a golf course, since the load on the mowing blade is small, the number of revolutions of the general-purpose power source 16 can be increased to be higher than the case of mowing grass in the field.

FIG. 6 shows a case in which a plurality of operating ranges, specifically a fourth operating range D and a fifth operating range E are set as the operating ranges of the work machine. A higher limit value R1 of the fourth operating range D and a higher limit value R2 of the fifth operating range E are smaller than the higher limit value R0 of the third operating range C, and the higher limit R1 of the fourth operating range D is smaller than the higher limit value R2 of the fifth operating range E. For example, the operator operating the work machine may select one of the fourth operating range D and the fifth operating range E from the input/output unit 50 depending on a work target, and perform work. Thus, by having a plurality of operating ranges, the work machine can be protected according to work.

(Configurations Supported by the Embodiment)

The above-described embodiment supports the following configurations.

(Configuration 1) A machine including: a general-purpose power source that is a power source for general purposes and is configured to operate within a first operating range for a predetermined physical quantity; a driven body to be driven by power of the general-purpose power source; and a control device for outputting an instruction to the general-purpose power source, wherein a second operating range is defined for the predetermined physical quantity, and the control device instructs the general-purpose power source to operate within the second operating range when the driven body is driven.

According to such a configuration, an excessive load will not be placed on the driven body. It is therefore possible to protect the driven body.

(Configuration 2) The machine defined in configuration 1, wherein the higher limit value of the first operating range is greater than the higher limit value of the second operating range.

According to such a configuration, an excessive load will not be placed on the general-purpose power source. It is therefore possible to protect the general-purpose power source mounted on the machine.

(Configuration 3) The machine defined in configuration 1 or 2, wherein the lower limit value of the first operating range is smaller than the lower limit value of the second operating range.

According to such a configuration, an excessive load will not be placed on the general-purpose power source. It is therefore possible to protect the general-purpose power source mounted on the machine.

(Configuration 4) The machine defined in any one of configurations 1 to 3, wherein at least one of the higher limit value and the lower limit value of the second operating range is changeable.

According to such a configuration, it is possible to change the operating range, depending on a load placed on the driven body. It is therefore possible to protect the driven body.

(Configuration 5) The machine defined in any one of configurations 1 to 4, wherein the control device executes a protection operation when the predetermined physical quantity exceeds the second operating range.

According to such a configuration, an excessive load will not be placed on the driven body. It is therefore possible to protect the driven body.

(Configuration 6) The machine defined in configuration 5, wherein the control device instructs the general-purpose power source to stop when the predetermined physical quantity exceeds a predetermined threshold value set outside the second operating range.

According to such a configuration, an excessive load will not be placed on the driven body. It is therefore possible to protect the driven body.

It should be noted that the above embodiment shows one aspect to which the present invention is applied, and the present invention is not limited to the above embodiment.

REFERENCE SIGNS LIST

-   -   10 Control device;     -   16 General-purpose power source;     -   18 Determination unit;     -   A First operating range;     -   B Second operating range;     -   H0 Higher limit value of first operating range;     -   L0 Lower limit value of first operating range;     -   H1 Higher limit value of second operating range; and     -   L1 Lower limit value of second operating range 

What is claimed is:
 1. A machine comprising: a general-purpose power source that is a power source for general purposes and is configured to operate within a first operating range for a predetermined physical quantity; a driven body to be driven by power of the general-purpose power source; and a control device for outputting an instruction to the general-purpose power source, wherein a second operating range is defined for the predetermined physical quantity, and the control device instructs the general-purpose power source to operate within the second operating range when the driven body is driven.
 2. The machine according to claim 1, wherein a higher limit value of the first operating range is greater than a higher limit value of the second operating range.
 3. The machine according to claim 1, wherein a lower limit value of the first operating range is smaller than a lower limit value of the second operating range.
 4. The machine according to claim 1, wherein at least one of the higher limit value and the lower limit value of the second operating range is changeable.
 5. The machine according to claim 1, wherein the control device executes a protection operation when the predetermined physical quantity exceeds the second operating range.
 6. The machine according to claim 5, wherein the control device instructs the general-purpose power source to stop when the predetermined physical quantity exceeds a predetermined threshold value set outside the second operating range. 